body{
    background: url("./img/summer.jpg") no-repeat;
    background-size: cover;  //只支持IE9+
    -webkit-background-size: cover; //webkit核心
    -moz-background-size: cover; //FF核心
    -o-background-size: cover; //应该是Opera核心吧，反正不是IE的，就先不管它了
    /*animation-name:myfirst;*/
    /*animation-duration:12s;*/
    /*!*变换时间*!*/
    /*animation-delay:2s;*/
    /*!*动画开始时间*!*/
    /*animation-iteration-count:infinite;*/
    /*!*下一周期循环播放*!*/
    /*animation-play-state:running;*/
    /*动画开始运行*/
}
/*@keyframes myfirst*/
/*{*/
    /*0%   {background:url("./img/spring.jpg");}*/
    /*34%  {background:url("./img/summer.jpg");}*/
    /*67%  {background:url("./img/autumn.jpg");}*/
    /*100% {background:url("./img/winter.jpg");}*/
/*}*/
.form{
    background: rgba(255,255,255,0.2);
    width:400px;
    margin-top:120px;
    float: right;
}
/*阴影*/
.fa{display: inline-block;top: 27px;left: 6px;position: relative;color: #ccc;}
input[type="text"],input[type="password"]{padding-left:26px;}
.checkbox{padding-left:21px;}